How should Ventricular Arrhythmias be Classified and which Patients should be Treated

It is the purpose of this chapter to examine two questions with respect to ventricular arrhythmias: (1) how should ventricular arrhythmias be classified? and (2) which ventricular arrhythmias should be treated? The first question has to do with deriving the useful information on the relationships between ventricular arrhythmias and outcome in observational studies or experimental studies. The purpose may be to estimate the association of ventricular arrhythmias and another factor, e.g., left ventricular dysfunction or cardiac death. Or, the purpose may be to judge the effect of a treatment on ventricular arrhythmias. The second question has to do with selection of patients for treatment in drug trials or clinical practice. We will consider both of the questions in the context of patients who are about to be discharged from hospital after myocardial infarction. We selected this group for several reasons. First, this is a common problem. Second, the year after myocardial infarction is a period of high risk for death. Third, ventricular arrhythmias are thought to contribute to post–infarction death.